code: def test_to_params_nested(self, empty_registrable):
      # Test how registrable disambiguates the _to_params when there is nested
      # registrables.
      class NestedBase(empty_registrable):
          pass
  
      @NestedBase.register("nested")
      class NestedClass(NestedBase):
          pass
  
      obj = NestedClass()
      assert obj.to_params().params == {"type": "nested"}
  
imports: import inspect
  import os
  from typing import List
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.registrable import Registrable
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.util import push_python_path
  from allennlp.data.dataset_readers.dataset_reader import DatasetReader
  from allennlp.data.token_indexers.token_indexer import TokenIndexer
  from allennlp.data.tokenizers.tokenizer import Tokenizer
  from allennlp.modules.text_field_embedders.text_field_embedder import TextFieldEmbedder
  from allennlp.modules.token_embedders.token_embedder import TokenEmbedder
  from allennlp.nn.regularizers.regularizer import Regularizer
label_desc: Use image node_id 12 for calling the TestRegistrable obj's underlying member method code with example usage: obj.test_to_params_nested(empty_registrable) without return types